Inoperable Left Renal Vein Leiomyosarcoma Refractory to Chemotherapy Invades Inferior Vena Cava and Right Atrium: A Case Report.

Mesenchymal stem cells differentiate into a plethora of cell types. These differentiated cell types include osteoblasts, chondrocytes, myocytes, and adipocytes. Sarcomas occur secondary to malignant transformation of these mesenchymal, pluripotent stem cells. Involuntary smooth muscle is responsible for the make up of hollow organs and vasculature in our body and is regulated by our autonomic nervous system, hormones, as well as chemical and local mediators. Cancer involving smooth muscle cells is designated as leiomyosarcoma (LMS). LMS can arise from any location in the body where smooth muscle is present and is frequently reported in the abdomen and pelvis, as well as the trunk, extremities, and throughout the retroperitoneum.